WASHINGTON — The Department of Agriculture yesterday declared safe for human consumption an experimental variety of genetically engineered rice found to have contaminated the U.S. rice supply this summer.

The move by the Animal and Plant Health Inspection Service to deregulate the special long-grain rice, LL601, was seen as a legal boon to its creator, Bayer CropScience of Research Triangle Park, N.C. The company applied for approval shortly after the widespread contamination was disclosed in August and now faces a class-action lawsuit filed by hundreds of farmers in Arkansas and Missouri.

The experimental rice, designed to resist Bayer's Liberty weed killer, escaped from Bayer's test plots after the company dropped the project in 2001. The resulting contamination, once it became public, prompted countries around the world to block rice imports from the United States, sending rice futures plummeting and farmers into fits.

In approving the rice, the USDA allowed Bayer to take a regulatory shortcut and skip many of the usual safety tests by declaring that the new variety is similar to ones already approved, in this case two varieties of biotech rice that Bayer never commercialized because farmers did not want them in their fields. The department gave its preliminary approval Sept. 8.

"The protein in the company's herbicide-tolerant rice varieties ... is well known to regulators, who have affirmed the rice poses no human health or environmental concern," said Greg Coffey, a Bayer spokesman.

Coffey said the company has no plans to sell the newly approved variety.

Joseph Mendelson, legal director of the nonprofit Center for Food Safety, said the quick approval shows that the USDA is more concerned about the fortunes of the biotechnology industry than about consumers' health.

"USDA is telling agricultural biotechnology companies that it doesn't matter if you're negligent, if you break the rules, if you contaminate the food supply with untested genetically engineered crops, we'll bail you out," Mendelson said in a statement.

"In effect, USDA is sanctioning an 'approval-by-contamination' policy that can only increase the likelihood of untested genetically engineered crops entering the food supply in the future," he said.

Most critics agree that the new rice is safe to eat. The bacterial gene that is in LL601 is also in several approved varieties of engineered corn, canola and cotton. Experts say the key gene in the new rice is sure to move via pollen into red rice, a weedy relative of white rice and the No. 1 plant pest for rice farmers in the South.